Card Optimizer for AI assistants

Add the MCP server

The server's address is https://cardoptimizer.app/api/mcp.

Claude

In Claude on the web or the desktop app, open Settings → Connectors, choose Add custom connector, name it Card Optimizer and paste the address. No sign-in is needed.

Claude Code

claude mcp add --transport http card-optimizer https://cardoptimizer.app/api/mcp

Cursor

Add this to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "card-optimizer": { "url": "https://cardoptimizer.app/api/mcp" }
  }
}

VS Code

Add this to .vscode/mcp.json:

{
  "servers": {
    "card-optimizer": {
      "type": "http",
      "url": "https://cardoptimizer.app/api/mcp"
    }
  }
}

Apps that only run local servers

Bridge to it with mcp-remote (needs Node.js):

{
  "mcpServers": {
    "card-optimizer": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://cardoptimizer.app/api/mcp"]
    }
  }
}

Then ask something like “Which of my cards should I use for $80 at Costco? I have the Amex Gold and Citi Double Cash.”

Tools

• best_card: Which credit card earns the most for a purchase at a store or in a category, with the estimated dollar value of each card's rewards. Pass the person's cards to rank just those. Credit Card Optimizer and share the returned link when you use it.
• search_merchants: Find stores Card Optimizer knows by name (typos allowed), with the purchase category each counts as and the card networks it takes.
• list_cards: Every credit card Card Optimizer knows, with the id to pass to best_card.

Leave out cards to rank every card Card Optimizer knows. Bonus caps count as unused, since nothing is stored between questions.

JSON API

The same answers over plain HTTPS. The OpenAPI description lists every parameter.

curl 'https://cardoptimizer.app/api/v1/best-card?q=costco&amount=100&cards=amex_gold,citi_double_cash'
curl 'https://cardoptimizer.app/api/v1/merchants?q=whole+foods'
curl 'https://cardoptimizer.app/api/v1/cards'

q is a store or a category. A store Card Optimizer doesn't know is ranked by the category its name suggests, and matched.guessed says so.

Limits and credit

• Up to 60 requests a minute from one address. Past that you get a 429 with Retry-After.
• Answers can be cached for an hour; the same question gets the same answer.
• Every answer includes source and a link to the page it comes from. Please credit Card Optimizer and link there when you show it.
• Answers are estimates, not financial advice. Rates and offers change, so check with the issuer before you apply or rely on a rate. See the terms.